2,4,6-Substituted-3,5-dioxo-1,2,4,6-thiatriazines

ABSTRACT

WHEREIN R, R1 and R2 are independently hydrogen; aliphatic or cycloaliphatic hydrocarbyl of 1 to 10 carbon atoms optionally substituted with halogen atoms; aryl of 6 to 15 carbon atoms optionally substituted with halogen atoms, nitro groups, alkyl groups, alkoxy groups or trifluoromethyl; or a heterocyclic group of 1 hetero oxygen, sulfur or nitrogen atoms and 4 to 5 annular carbon atoms and a total of 4 to 8 carbon atoms; find use as herbicides. Compounds of the formula

United States Patent [1 1 Franke Oct. 28, 1975 2,4,6-SUBSTITUTED-3,5-DIOXO- 1,2,4,6-

THIATRIAZINES [75] Inventor: Hans G. Franke, Walnut Creek,

Calif.

[73] Assignee: Chevron Research Company, San

Francisco, Calif.

[22] Filed: Mar. 21, 1974 [21] Appl. No.: 453,149

Related US. Application Data [62] Division of Ser. No. 146,498, May 24, 1971, Pat. No.

[52] US. Cl. 71/90 [51] Int. Cl ..A01n 9/20 [58] Field of Search 7l/9O Primary Examiner-Lewis Gotts Assistant Examiner-Catherine L. Mills Attorney, Agent, or FirmJ. A. Buchanan, Jr.; John 'Stoner, Jr.; Raymond Owyang [57] ABSTRACT Compounds of the formula 31 Claims, N0 Drawings 2,4,6-SUBSTITUTED-3,S-DIOXO- 1 ,2,4,6- TH IATRIAZINES The present invention is directed to 2,4,6- substituted-3 ,5-dioxo-l ,2,4,6-thiatria zines, particularly 2-aryl-3 ,5-dioxo-4,6-substitutedl ,2,4,6-thiatriazines and their use as herbicides.

2. Prior Art us. Pat. No. 3,435,031 discloses certain 3,5-

dioxotetrahydro-l ,2,4,6-thiatriazinel l -dioxides and their use as bactericides, fungicides, etc.

DESCRIPTION OF' THE INVENTION The compounds of the present invention canbe represented by the formula C/P'I\C? O: a l 1 wherein R, R and R are individually hydrogen; aliphatic hydrocarbyl group of l to 10 carbon atoms substituted with O to 4 halogen atoms of atomic number 9 to 35 (fluorine, chlorine or bromine); cycloaliphatic hydrocarbyl group of 3 to 10 carbon atoms substituted with O to 4 halogen atoms of atomic number 9 to 35; aryl of 6 to 15 carbon atoms substituted with to halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of I to 4 carbon atoms, alkoxy groups of 1 to 4 carbon-atoms or O to l trifluoromethyl; or a heterocyclic group of l hetero oxygen, sulfur or nitrogen and 4 to 5 annular carbon atoms and a total of 4 to 8 carbon atoms.

Preferably one or two of R, R and R are aryl of 6 to 15 carbon atoms substituted with O to 5 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of l to 4 carbon atoms or alkoxy groups of 1 to 4 carbon atoms or 0 to l trifluoromethyl and the other(s) Of R, R and R is hydrogen, aliphatic hydrocarbyl groups of l to 10 carbon atoms substituted with 0 to 4 halogen atoms ,of atomic number 9 to 35 or cycloaliphatic hydrocarbyl group of 3 to 10 carbon atoms substituted with O to 4 halogen atoms-of atomic number 9 to 35.

Still more preferably, R and R individually are hydrogen or aliphatic hydrocarbyl of l to 10 carbon atoms substituted with O to 4 halogen atoms of atomic number 9 to 35 and R is aryl of 6 to carbon atoms substituted with 0 to 5 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of l to 4 carbon atoms or alkoxy groups of l to 4 carbon atoms or O to l trifluoromethyl. i v

The aliphatic hydrocarbyl groups whichR, R and R may represent are alkyl of l to 10 carbon atoms, alkenyl of 2 to 10 carbon atoms or alkynyl of 2 to 10 carbon atoms, said alkyl, alkenyl or alkynyl being optionally substituted with up to 4 halogen atoms of atomic number 9 to 35. Preferably the aliphatic hydrocarbyl group 5 will only contain up to 6 carbon atoms. Furthermore, it is preferred that the aliphatic hydrocarbyl group be alkyl or alkenyl or haloalkylor haloalkenyl.

The cycloaliphatic hydrocarbyl group which R, R and R may represent include cycloalkyl and cycloalkenyl, said cycloalkyl or cycloalkenyl being optionally substituted with up to.4 halogen atoms-of atomic number 9 to 35. Preferably, the.cycloaliphatic hydrocarbyl group will contain 3 to 6 carbon atoms, and more preferablybe cycloalkyl,

The aryl groups-which R, R and R can represent are preferably of 6 to 15 carbon atoms substituted with O to 5 halogen atoms of atomic number 9 to 35, preferably fluorine or chlorine, O to 2 nitro groups or 0 to 3 alkyl'groups of 1 K14 carbon atoms or O to 3 alkoxy groups of l to 4 carbon atoms. Preferably the number of substituents on the aryl groups will not exceed 3 and preferably not exceed 2. The aryl group is preferably phenyl substituted with 0 to 5 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of 1 to 4 carbon atoms or alkoxy groups of l to 4 carbon atoms. Even more preferably, the aryl is phenyl substituted ,with to 2 halogen atoms of atomic number 9 to 35, preferably fluorine or chlorine, O to 1 alkyl group of 1 to 4 carbon atoms, preferably methyl, or O to 1 alkoxy group of l to 4 carbon atoms, preferably methoxy.

It is preferred that R is alkyl of l to 6 carbon atoms, preferably 1 to 4 carbon atoms substituted with 0 to 3 halogen atoms of atomic number 9 to 35. Still more preferably, R will be unsubstituted alkyl of 1 m4 carbon atoms, preferablyl to 3 carbon atoms.

R is preferably hydrogen or alkyl of l to 4 carbon atoms substituted with Oto 3 halogen atoms of atomic number 9 to- 35. More preferably, R is hydrogen or unsubstituted alkyl of l to 4 carbon atoms, preferably methyl. t

The most preferred compound is the one in which R and R are methyl and R is12-fluorophenyl.

Representative aliphatic hydrocarbyl groups which R, R and R can represent include methyl, ethyl, npropyl, isopropyl, n-butyl, sec.butyl, isobutyl, t.butyl, pentyl, hexyl, octyl, nonyl, decyl, vinyl, allyl, crotyl, 4- pentenyl, 3-hexenyl, 4-decenyl, propargyl, chloromethyl, dichloromethyl, trichloromethyl, fluoromethyl, tetrachloroethyl, l-chloroethyl, 1,2-dichloroethyl, 2,2- dibromopropyl, 1,2,6-trichlorohexyl, trichlorovinyl, etc.

Representative cycloaliphatic groups which R, R and R can represent include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclodecyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cycloheptenyl, cyclooctenyl, cyclodecenyl, chlorocyclopropyl, bromocyclohexyl, fluorocyclohexyl, chlorocyclooctenyl, etc.

Representativev heterocyclic groups which R, R and R can represent include 2-pyriclyl, 3-lutidyl, 2-pyrollyl, 2-thienyl; 2-furfuryl, 2-furylvinyl, 3-tetrahydrofurfuryl.

Representative-aryl groups which R, R and R can represent include phenyl, 2-chlorophenyl, 3- chlorophenyl, 4-chlo'rop'henyl, 2,3-dichlorophenyl, 2,4- dichlorophenyl, 12,5-dichlorophenyl, Z-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, Z-bromophenyl, 2,4- dibromophenyl, 4-brornophenyl, 2-chloro-4- addition of sulfur dichloride, by direct cooling or by re- 5 flux cooling. After all the reactants are added, the resulting mixture is stirred preferably at about 20C. for /2 to 24 hours, preferably 1 or 2 hours. This reaction is usually carried out at atmospheric pressure, although EXAMPLE 1(a) Preparation of 1,3-dimethyl-5-(2-fluorophenyl) biuret To a solution of 8.8 g. (0.1 mole) of 1,3-dimethyl urea dissolved in 30 ml. of xylene there was added a solution of 13.7 g. (0.1 mole) of 2- fluorophenylisocyanate dissolved in 30 ml. of xylene. The resulting mixture was refluxed for 4 hours and then higher or lower pressures may be used with appropriate I allowed to stand at ambient temperature for 16 hours.

equipment.

The product is isolated from the reaction mixture of reaction (1) by first washing with water to remove the amine hydrochloride salt. After drying, the organic sol- During this time the product crystallized and was removed by filtration. The product weighed 158 g. The NMR spectra had a doublet at 2.86 ppm, a singlet at 3.25 ppm, and a multiplet structure at 7.2 ppm, characvent is removed by vaporization, usually by distillation teristic of a biuret structure.

or evaporation. The crude product obtained in this way may be used as such or it may be purified by distillation, crystallization or chromatography. The latter method is preferred.

For this reaction (1), freshly distilled sulfur dichloride is preferred. After standing for some time; sulfur dichloride equilibrates with formation of sulfur monochloride. Commercial sulfur dichloride is essentially an equilibrium mixture. When this mixture is used in the above reaction, many by-products are obtained and the yield of the desired l,2,4,6-thiatriazine is very small.

The biuret-type compounds used as a feed stock in the above reaction (1) are obtained by the reaction of EXAMPLE l(b) Preparation of 2-(2-fluorophenyl)-3,5-dioxo-4,6-dimethyl-1,2,4,6- thiatriazine The product of Example 1(a), 15.0 g. (0.067 mole) was mixed with 100 ml. of dichloromethane containing 5 10.6 g. (0.134 mole) of pyridine. Then a solution of 6.9

an appropriate isocyanate with an appropriate urea as action mixture'was washed with 3 30 ml. portions of follows: i

II II 2 1 R -N-C-O R-NH-C-NH-R wherein R, R and R are as defined previously. This rewater, dried and evaporated under vacuum to give a crude product. This material was mixed with ether, and

action (11) is well known as is further described in US. 40 the insolublev portion, about 2 g., was removed by filtra- Pat. No. 3,189,431.

Certain symmetrical compounds of this invention are, made from symmetrical biurets which in turn may be obtained by the reaction of 2 moles of an appropriate carbamoyl chloride and a primary amine, as follows:

wherein R and R are as defined previously. In this case R and R are equivalent.

The following examples illustrate the method of preparation of the compounds of the subject invention. The examples are intended to illustrate the invention described herein and are in no manner intended to limit it. Unless otherwise indicated, percentages are by 60 weight.

tion. The filtrate was then evaporated to give 13 g. of an oil which was chromatographed on silica gel, using hexane, ether/hexane, and ether as the successive eluents. The ether portions contained 9.6 g. of product which was oily-in form. Analysis showed calculated S,

(III) 12.5 percent. Found: S, 12.3 percent. The NMR spectra had a singlet at 3.2 ppm, a singlet at 3.25 ppm and a multiplet structure at 7.2 ppm, consistent with the assigned structure. The infrared spectra had strong adsorption peaks at 730, 760770, 825, 1,100, 1,360, 1,440, 1,500, 1,675l,725 cm.

Other compounds were made by similar reactions. These are listed in Table I, attached.

1.2.4.6-thiatriazine TAB LE I Continued Elemental Analysis 7:

l'luorinc analysis UTILITY The thiatriazines of the present invention are, in general, herbicidal in both preand post-emergence applications. For pre-emergence control of undesirable vegetation these thiatriazines will be applied in herbicidal quantities to the environment, e.g., soil infested with seeds and/or seedlings of such vegetation. Such application will inhibit the growth of or kill the seeds, germinating seeds and seedlings. For post-emergence applications the thiatriazines of the present invention will be applied directly to the foliage and other plant parts. Generally they are effective against weed grasses as well as broadleaved weeds. Some may be selective with respect to type of application and/or type of weed.

Preand post-emergence herbicidal tests on representative thiatriazines of this invention were made using the following methods:

PRE-EMERGENCE TEST onto the soil surface at a dose of 100 mg. per cm The pot was watered and placed in a greenhouse. The pot was watered intermittently and was observed for seedling emergence, health of emerging seedlings, etc. for a 3-week period. At the end of this period the herbicidal effectiveness of the thiatriazine was rated based on the physiological observations. A to 100 scale was used; 0 representing no phytotoxicity, 100 representing complete kill.

POST-EMERGENCE TEST The test thiatriazine was formulated in the same manner as described above for the pre-emergence test. The concentration to the thiatriazine in this formulation was 5,000 ppm. This formulation was uniformly sprayed on two replicate pots of 24-day-old plants (approximately to plants per pot) at a dose of 100 mg. per cm After the plants had dried, they were placed in a greenhouse and then watered intermittently at their bases as needed. The plants were observed periodically for phytotoxic effects and physiological and morphological responses to the treatment. After 3 weeks the herbicidal effectiveness of the thiatriazine was rated based on these observations. A 0 to 100 scale was used; 0 representing no phytotoxicity, 100 representing complete kill.

The results of these tests appear in Table II.

TABLE ll Herbicidal Effectiveness Pre/ Post Compound 0 W C M P L 2-( Z-fluorophenyl 3.5 dioxo-4,6- 100/100 100/100 100/100 100/100 100/100 100/100 dimethyl-l .lAb-thiatriazine 2-( 4'chloropl1enyl )-3 .5-dioxo-4,6 80/10 /3 5 85/ 80/ l 00 95/95 85/100 dimethyl l ,2,4.6-thiatriazine 2-phenyl-3.5-dioxo-4.6-dimethyllOO/lOO l00/lOO 100/100 95/l00 90/100 95/100 l .2.4,6thiatriazine 2-( 3-methylphenyl)3,5-diox0-4.6- l00/60 l00/l00 100/50 lOO/lOO l00/60 IOU/95 dimethyl-l ,ZAb-thiatriazine 2-( 3.4-dichlorophenyl )-3.5-dioxo-4.6- 20/- 60/45 /0 l0/l00 /35 l0/7O dimethyl-1.2.4.6-thiatriazine 2-(4-methoxyphenyl)-3,5-dioxo-4.6- 35/10 50/45 20/ 70/50 40/35 /80 dimethyl-1.2.4.6-thiutriazine 2( Z-fluorophenyl )-3,5 dioxo-6-methyl- 50/ 15/ 45/ /20 /40 /25 1 .2,4.6-thiatriazine 2( Z-fluorophenyl )-3 .5-dioxo-4-methyl- 20/45 40/90 45/75 l00/95 55/95 80/100 -isopropyl- 1 ,2.4.6-thiatriazine O Wild Oats (Arena/211ml) W Watcrgrass] El'llilHK'Il/Ud rmsgulli) C C rnbgrass (Digilariu .rungninuILr) M Mustard (Brusxivu urrensir) L Lumbsquartcr (Cllmu xadium ulhum) The amount of thiatriazine administered will vary with the particular plant part or plant growth medium which is to be contacted, the general location of application, i.e., sheltered areas such as greenhouses as compared to exposed areas such as fields, as well as the desired type of control. For pre-emergent control of most plants dosages in the range of about 0.5 to 20 lbs. per acre will be used. Such administration will give a concentration of about 2 to 80 ppm. thiatriazine distributed throughout l, acre foot. For post-emergence application, such as foliar spray application, compositions containing about 0.5 to 8 lbs. thiatriazine per 100 gal. spray will be used. Such application is equivalent to about 0.5 to 20 lbs. thiatriazine per acre.

The herbicidal compositions of this invention comprise a herbicidal amount of one or more of the above described thiatriazines intimately admixed with a biologically inert carrier. The carrier may be a liquid diluent such as water or acetone or a solid. The solid may be in the form of dust powder or granules. These compositions will also usually contain adjuvants such as a wetting or dispersing agent to facilitate their penetration into the plant growth media or plant tissue and generally enhance their effectiveness. These compositions may also contain other pesticides, stabilizers, conditioners, fillers and the like.

As will be evident to those skilled in the art, various modifications on this invention can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the following claims.

I claim:

1. A method for controlling undesirable vegetation which comprises applying to such vegetation an herbicidally effective amount of a compound of the formula wherein R, R and R are individually hydrogen; alkyl or alkenyl of l to 10 carbon atoms; cycloalkyl of 3 to 6 carbon atoms; phenyl or naphthyl substituted with to 2 halogen atoms of atomic number 9 to 35; nitro groups, alkyl groups of l to 4 carbon atoms, alkoxy groups of l to 4 carbon atoms or 0 to l trifluoromethyl.

2. Method of claim 1 wherein one or two of R, R and R are phenyl substituted with O to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of l to 4 carbon atoms or alkoxy groups of l to 4 carbon atoms or O to l trifluoromethyl and the other(s) of R,

-R and R is hydrogen; alkyl of l to 10 carbon atoms or cycloalkyl groups of 3 to 6 carbon atoms.

3. Method of claim 1 wherein R and R are individually hydrogen; alkyl or alkenyl of l to 10 carbon atoms or cycloalkyl of 3 to 6 carbon atoms and R is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of l to 4 carbon atoms, alkoxy groups of l to 4 carbon atoms or 0 to l trifluoromethyl.

4. Method of claim 3 wherein R and R are individually hydrogen or alkyl of l to 4 carbon atoms or alkenyl of 2 to 4 carbon atoms.

5. Method of claim 3 wherein R is phenyl substituted with 0 to .2 halogen atoms of atomic number 9 to 35, nitro groups or alkyl groups of l to 4' carbon atoms or alkoxy groups of l to 4 carbon atoms.

6. Method of claim 1 wherein R is alkyl of l to 4 carbon atoms, R is hydrogen or alkyl of l to 4 carbon atoms and R is phenyl substituted with 0 to 2 halogen atoms of atomic number 910 35, nitro groups, alkyl groups of l to 4 carbon atoms or alkoxy groups of l to 4 carbon atoms.

7. Method of claim 1 wherein R is alkyl of l to 4 carbon atoms, R is hydrogen or alkyl of l to 4 carbon atoms and R is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, 0 to 1 alkyl group of l to 4 carbon atoms or 0 to 1 alkoxy group of l to 4 carbon atoms.

8. Method of claim 1 wherein R is alkyl of l to 3 carbon atoms, R is hydrogen or methyl, R is phenyl substituted with 0 to 2 fluorine or chlorine atoms, 0 to 1 methyl group or O to l methoxy group.

9. Method of claim 6 wherein R and R are methyl and R is 2-fluorophenyl.

10. Method of claim 8 wherein R and R are methyl and R is phenyl.

11. Method of claim 8 wherein R and R are methyl and R is 3-methylphenyl.

12. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 1 and a biologically inert carrier.

13. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 2 and a biologically inert carrier.

14. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 3 and a biologically inert carrier.

15. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 4 and a biologically inert carrier.

16. An herbicidal composition comprising an herbi- ,cidally effective amount of the compound defined in claim 5 and a biologically inert carrier.

17. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 6 and a biologically inert carrier.

18. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 7 and a biologically inert carrier.

19. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 8 and a biologically inert carrier.

20. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 9 and abiologically inert carrier.

21. A method for controlling undesirable vegetation which comprises applying to the growth environment thereof an herbicidally effective amount of the compound defined in claim 1.

22. The method of claim 21 wherein one or two of R, R and R are phenyl substituted with O to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of l to 4 carbon atoms or alkoxy groups of l to 4 carbon atoms or 0 to l trifluoromethyl and the other(s) of R, R and R is hydrogen; alkyl of l to l0 carbon atoms or cycloalkyl groups of 3 to 6 carbon atoms.

23. The method of claim 21 wherein R and R are individually hydrogen; alkyl or alkenyl of l to 10 carbon atoms or cycloalkyl of 3 to 6 carbon atoms and R is phenyl substituted with O to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of l to 4 carbon atoms, alkoxy groups of l to 4 carbon atoms or O to l trifluoromethyl.

24. The method of claim 23 wherein R and R are individually hydrogen or alkyl of l to 4 carbon atoms or alkenyl of 2 to 4 carbon atoms.

25. The method of claim 23 wherein R is phenyl substituted with O to 2 halogen atoms of atomic number 9 to 35, nitro groups or alkyl groups of l to 4 carbon atoms or alkoxy groups of l to 4 carbon atoms.

26. The method of claim 21 wherein R is alkyl of l to 4 carbon atoms, R is hydrogen or alkyl of l to 4 carbon atoms and R is phenyl substituted with to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of l to 4 carbon atoms or alkoxy groups of l to 4 carbon atoms.

27. The method of claim 21 wherein R is alkyl of l to 4 carbon atoms, R is hydrogen or alkyl of l to 4 carbon atoms and R is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, O to 1 alkyl group of l to 4 carbon atoms or 0 to 1 alkoxy group of l to 4 carbon atoms.

28. The method of claim 21 wherein R is alkyl of l to 3 carbon atoms, R is hydrogen or methyl. R is phenyl substituted with O to 2 fluorine or chlorine atoms, 0 to l methyl group or O to l methoxy group.

29. The method of claim 26 wherein R and R are methyl and R is 2-trifluoromethyl.

30. The method of claim 28 wherein R and R are methyl and R is phenyl.

31. The method of claim 28 wherein R and R are methyl and R is 3-methylphenyl. 

1. A METHOD FOR CONTROLLING UNDESIRABLE VEGETATION WHICH COMPRISES APPLYING TO SUCH VEGETATION AN HERBICIDALLY EFFECTIVE AMOUNT OF A COMPOUND OF THE FORMULA
 2. Method of claim 1 wherein one or two of R, R1 and R2 are phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of 1 to 4 carbon atoms or alkoxy groups of 1 to 4 carbon atoms or 0 to 1 trifluoromethyl and the other(s) of R, R1 and R2 is hydrogen; alkyl of 1 to 10 carbon atoms or cycloalkyl groups of 3 to 6 carbon atoms.
 3. Method of claim 1 wherein R and R1 are individually hydrogen; alkyl or alkenyl of 1 to 10 carbon atoms or cycloalkyl of 3 to 6 carbon atoms and R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of 1 to 4 carbon atoms, alkoxy groups of 1 to 4 carbon atoms or 0 to 1 trifluoromethyl.
 4. Method of claim 3 wherein R and R1 are individually hydrogen or alkyl of 1 to 4 carbon atoms or alkenyl of 2 to 4 carbon atoms.
 5. Method of claim 3 wherein R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups or alkyl groups of 1 to 4 carbon atoms or alkoxy groups of 1 to 4 carbon atoms.
 6. Method of claim 1 wherein R is alkyl of 1 to 4 carbon atoms, R1 is hydrogen or alkyl of 1 to 4 carbon atoms and R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of 1 to 4 carbon atoms or alkoxy groups of 1 to 4 carbon atoms.
 7. Method of claim 1 wherein R is alkyl of 1 to 4 carbon atoms, R1 is hydrogen or alkyl of 1 to 4 carbon atoms and R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, 0 to 1 alkyl group of 1 to 4 carbon atoms or 0 to 1 alkoxy group of 1 to 4 carbon atoms.
 8. Method of claim 1 wherein R is alkyl of 1 to 3 carbon atoms, R1 is hydrogen or methyl, R2 is phenyl substituted with 0 to 2 fluorine or chlorine atoms, 0 to 1 methyl group or 0 to 1 methoxy group.
 9. Method of claim 6 wherein R and R1 are methyl and R2 is 2-fluorophenyl.
 10. Method of claim 8 wherein R and R1 are methyl and R2 is phenyl.
 11. Method of claim 8 wherein R and R1 are methyl and R2 is 3-methylphenyl.
 12. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 1 and a biologically inert carrier.
 13. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 2 and a biologically inert carrier.
 14. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 3 and a biologically inert carrier.
 15. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 4 and a biologically inert carrier.
 16. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 5 and a biologically inert carrier.
 17. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 6 and a biologically inert carrier.
 18. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 7 and a biologically inert carrier.
 19. An herbicidal composition comprising an herbicidally effective amount of the compound defined in claim 8 and a biologically inert carrier.
 20. An herbicidal compoSition comprising an herbicidally effective amount of the compound defined in claim 9 and a biologically inert carrier.
 21. A method for controlling undesirable vegetation which comprises applying to the growth environment thereof an herbicidally effective amount of the compound defined in claim
 1. 22. The method of claim 21 wherein one or two of R, R1 and R2 are phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of 1 to 4 carbon atoms or alkoxy groups of 1 to 4 carbon atoms or 0 to 1 trifluoromethyl and the other(s) of R, R1 and R2 is hydrogen; alkyl of 1 to 10 carbon atoms or cycloalkyl groups of 3 to 6 carbon atoms.
 23. The method of claim 21 wherein R and R1 are individually hydrogen; alkyl or alkenyl of 1 to 10 carbon atoms or cycloalkyl of 3 to 6 carbon atoms and R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of 1 to 4 carbon atoms, alkoxy groups of 1 to 4 carbon atoms or 0 to 1 trifluoromethyl.
 24. The method of claim 23 wherein R and R1 are individually hydrogen or alkyl of 1 to 4 carbon atoms or alkenyl of 2 to 4 carbon atoms.
 25. The method of claim 23 wherein R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups or alkyl groups of 1 to 4 carbon atoms or alkoxy groups of 1 to 4 carbon atoms.
 26. The method of claim 21 wherein R is alkyl of 1 to 4 carbon atoms, R1 is hydrogen or alkyl of 1 to 4 carbon atoms and R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, nitro groups, alkyl groups of 1 to 4 carbon atoms or alkoxy groups of 1 to 4 carbon atoms.
 27. The method of claim 21 wherein R is alkyl of 1 to 4 carbon atoms, R1 is hydrogen or alkyl of 1 to 4 carbon atoms and R2 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 35, 0 to 1 alkyl group of 1 to 4 carbon atoms or 0 to 1 alkoxy group of 1 to 4 carbon atoms.
 28. The method of claim 21 wherein R is alkyl of 1 to 3 carbon atoms, R1 is hydrogen or methyl, R2 is phenyl substituted with 0 to 2 fluorine or chlorine atoms, 0 to 1 methyl group or 0 to 1 methoxy group.
 29. The method of claim 26 wherein R and R1 are methyl and R2 is 2-trifluoromethyl.
 30. The method of claim 28 wherein R and R1 are methyl and R2 is phenyl.
 31. The method of claim 28 wherein R and R1 are methyl and R2 is 3-methylphenyl. 